Method and system for delivering dual layer hdtv signals through broadcasting and streaming

ABSTRACT

The present invention provides a method and system for delivering SDTV/HDTV services that achieves significant bandwidth savings, while keeping the existing SDTV transmission unchanged. In accordance with one embodiment of the invention, a system is provided for delivering HDTV signals. In this system, an HD enhancement layer containing an HD enhancement data stream is obtained\. The HD enhancement layer is delivered to a server to enable a subscriber to access the server, via a set top terminal, to receive the HD enhancement layer over a network system. In another embodiment of the invention, a base layer containing a SD data stream is also delivered to the set top terminal to allow the terminal to integrate the HD enhancement layer and the base layer into a HDTV output.

BACKGROUND OF THE INVENTION

The invention relates generally to digital broadcasting technologies,and more particularly to SDTV (standard definition TV)/HDTV (highdefinition TV) compatible broadcasting technologies.

Conventionally, TV service providers simultaneously broadcast SDTV(e.g., 720×576i, 50 Hz) and HDTV (e.g., 1920×1080i, 50 Hz) signals, bothcontaining the same programs, via satellite, cable, or terrestrialtransmission. As the laws have been passed in a number of countries,requiring complete migration from the SDTV to HDTV services in a fewyears, TV service providers will have to add more HDTV channels whilemaintaining some SDTV channels for backward compatibility so as toprovide TV viewers with a smooth transition. In order to add more SDTVand HDTV channels, it is necessary for TV service providers to moreefficiently use the available bandwidths.

In existing MPEG2 HDTV/SDTV compatible broadcasting techniques, a SDtransport stream (e.g. 4-6 Mbps) and a HD transport stream (e.g. 18Mbps), both containing the same program, are modulated andsimultaneously broadcasted on one standard analog channel (6 MHz, 24Mbps). A major drawback is that it takes the upper limit of thebandwidth within one analog channel leaving few bandwidth for themodulation overhead. The reason is that with the 4 Mbps and 18 Mbpsbeing allocated to the SD and HD transport streams, respectively, it canprovide only the lower limit of the quality for the SDTV and HDTVsignals. Thus, the conventional way of transmitting both HDTV and SDTVsignals within one analog channel leads to either a higher threshold forreceiving the HDTV and SDTV signals or a decline in the SDTV signalquality. Further, it requires two sets of encoders for encoding the HDTVand SDTV signals and also wastes the bandwidth by delivering duplicateSD portions of the contents.

A solution has been proposed to address the above drawbacks, whileattempting to maintain backward compatibility with the existing SDTVbroadcasting. The proposed solution utilizes a dual layer HDTVcompression technology to deliver the HDTV dual layer streams throughbroadcasting. However, because the compression technology fails toproduce significant bandwidth savings and requires substantial changesin the existing SDTV transmission systems, TV service providers arehesitant to use this solution. They are very reluctant to invest in therelated transmission systems without being able to realize significantbenefits.

Therefore, there is a need to provide an improved method and system fordelivering SDTV/HDTV services that can overcome the above drawbacks andachieve significant savings in the traditional broadcasting bandwidth,while keeping the existing SDTV transmission unchanged.

SUMMARY OF THE INVENTION

The present invention provides a method and system for deliveringSDTV/HDTV services that overcomes the drawbacks associated with theexisting broadcasting techniques and achieves significant bandwidthsavings, while keeping the existing SDTV transmission unchanged.

In accordance with one embodiment of the invention, a system is providedfor delivering HDTV signals. The system comprises means for obaining anHD enhancement layer containing an HD enhancement data stream, and meansfor delivering the HD enhancement layer to a server to enable a viewerto access the server, via a set top terminal, to receive the HDenhancement layer over a network system.

In accordance with another embodiment of the invention, the systemfurther comprises means for delivering a base layer containing a SD datastream to the set top terminal to allow the terminal to integrate the HDenhancement layer and the base layer into a HDTV output.

Other objects and attainments together with a fuller understanding ofthe invention will become apparent and appreciated by referring to thefollowing description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in further detail, and by way of example,with reference to the accompanying drawings wherein:

FIG. 1 shows an overview of the invention in which dual layer SDTV/HDTVdata streams are provided to TV viewers;

FIG. 2 is a functional block diagram of a HDTV STB in accordance withone embodiment of the invention; and

FIG. 3 is a functional diagram of a dual layer signal generation circuitwhich may be used to generate the dual layer signals.

Throughout the drawings, the same reference numerals indicate similar orcorresponding features or functions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an overview of the invention in which dual layer SDTV/HDTVdata streams are provided to TV viewers. The dual layer includes a SDbase layer containing a SD data stream and an HD enhancement layercontaining an HD enhancement data stream. The base layer is directly andindependently broadcast by a SDTV broadcasting system 12 and istransmitted via traditional media 16, e.g., terrestrial, cable,satellite, etc. A SDTV STB (set top box) 18 receives and decodes the SDdata stream and sends the decoded signals to a SDTV 20.

The HD enhancement data stream, on the other hand, is provided to astreaming server 32 for delivering to TV viewers over the Internet 36,through, e.g., an advanced broadband IP network that implements, forinstance, DVB-IPI (Digital Video Broadcasting Internet ProtocolInfrastructure) protocols. The advanced IP network can deliveraudio/video (A/V) data over the Internet while guaranteeing QoS (Qualityof Service). This saves the traditional broadcasting bandwidth, whilemaintaining backward compatibility with the conventional SDTVbroadcasting.

The data streams from the two layers are received by a HDTV STB 38. HDTVSTB 38 decodes the received signals, integrates them into a HDTV outputand then sends the HDTV output to a HDTV 40.

In this way, TV service providers could keep the SDTV broadcastingservice unchanged for SDTV subscribers, while providing the HDTV servicethrough the broadcasting and network streaming paths for another groupof subscribers who are willing to pay higher fees for a better A/Vquality. Meanwhile, there will be no meaningful output generated if onlythe enhancement layer is obtained via the Internet.

The two layers of the signals can be protected in different ways thatlead to a higher security for the contents. For example, the base layercan be protected in the same manner as that used in the existing SDTVbroadcasting. As to the enhancement layer, apart from using useridentification for viewing, copying protection can be achieved by usingtechnologies available for content streaming over an IP network.

FIG. 2 is a functional block diagram of HDTV STB 38 in accordance withan embodiment of the invention. HDTV STB 38 includes an Ethernet card42, a hard disk 44, a HD decoder 46, a tuner 52, a SD decoder 56, anup-scaling circuit 58, and an adder 66. HD decoder 46 receives theenhancement layer via Ethernet card 46 and decodes the data stream inthe enhancement layer. This can be done by steaming the enhancementlayer to HDTV STB 38 while a TV viewer is viewing the program, if thebandwidth of the IP network is sufficient. Otherwise, the enhancementlayer contents can be pre-downloaded and stored on hard disk 44 forsubsequent viewing by the TV viewer. The downloaded contents can beerased by the service provider afterwards.

SD decoder 56 receives the base layer via tuner 52 and decodes the datastream in the base layer. The output of SD decoder 56 is provided toup-scaling circuit 58 and is upgraded by circuit 58 to HD formatsignals. The outputs from HD decoder 46 and up-scaling circuit 58 arethen integrated by adder 66 to generate a HDTV output for delivering toHDTV 40.

FIG. 3 is a functional block diagram of a dual layer signal generationcircuit 70, which may be used to generate the base and enhancementlayers. Circuit 70 includes a down-scaling circuit 76, a SD encoder 82,an up-scaling circuit 86, an adder 92 and a HD encoder 96. In circuit70, the original HD signals are downgraded by down-scaling circuit 76 toSD format signals which are then encoded by SD encoder 82 to generatethe base layer for broadcasting to the SDTV subscribers. The encoded SDsignals are also upgraded by up-scaling circuit 96 to HD format signals.The upgraded signals and the HD signals are integrated by adder 92, andthe integrated signals are encoded by encoder 96 to generate theenhancement layer.

In FIG. 3, the MPEG2 compression technology may be used in SD encoder 82and HD encoder 96, so that conventional SD and HD encoders may beutilized. Alternatively, the MPEG2 compression technology may be usedonly in SD encoder 82, while the ITU H.264 compression technology may beused in HD encoder 96 to achieve much higher compression ratio.Additionally, if compatibility with the existing international standardsis not essential, the ITU H.264 compression technologies or othercompression technologies may be used in both the SD and HD encoders togenerate the dual layer signals with even higher coding efficiency.

While the invention has been described in conjunction with specificembodiments, it is evident that many alternatives, modifications andvariations will be apparent to those skilled in the art in light of theforegoing description. Accordingly, it is intended to embrace all suchalternatives, modifications and variations as fall within the spirit andscope of the appended claims.

1. A system for delivering high-definition (HD) TV signals, comprising:means for obtaining an HD enhancement layer containing an HD enhancementdata stream; and means for delivering the HD enhancement layer to aserver to enable a viewer to access the server, via a set top terminal,to receive the HD enhancement layer over a network system.
 2. The systemof claim 1, further comprising means for delivering a base layercontaining a standard definition (SD) data stream to the set topterminal to allow the terminal to integrate the HD enhancement layer andthe base layer into a HDTV output.
 3. The system of claim 2, wherein theobtaining means includes: means for generating the base layer; anupscaling circuit that is configured to upscale the base layer togenerate HD format signals; an adder, coupled to the upscaling circuit,that is configured to subtract the HD format signals from original HDsignals to generate enhanced signals; and a HD encoder, coupled to theadder, that is configured to encode the enhanced signals to generate theHD enhancement layer.
 4. The system of claim 3, wherein the means forgenerating the base layer includes: a downscaling circuit that isconfigured to downscale HD signals to generate SD format signals; and aSD encoder, coupled to the downscaling circuit, that is configured toencode the SD format signals to generate the base layer.
 5. The systemof claim 4, wherein the HD encoder encodes the enhanced signals usingITU H.264 compression technology.
 6. The system of claim 5, wherein theSD encoder encodes the SD format signals using MPEG2 compressiontechnology.
 7. The system of claim 5, wherein the SD encoder encodes theSD format signals using ITU H.264 compression technology.
 8. A set topterminal, comprising: means for decoding a high-definition (HD)enhancement layer containing an HD enhanced data stream; means fordecoding a base layer containing a standard-definition (SD) data stream;an upscaling circuit, coupled to the means for decoding a base layer,that is configured to upscale the decoded base layer to HD formatsignals; and means for integrating the decoded HD enhancement layer andthe HD format signals into a HDTV output.
 9. The terminal of claim 8,wherein the means for decoding an HD enhancement layer includes an HDdecoder that is configured to decode the HD enhancement layer.
 10. Theterminal of claim 9, wherein the means for decoding a base layerincludes: a tuner for tuning the base layer received; and a SD decoder,coupled to the tuner, that is configured to decode the base layer. 11.The terminal of claim 10, wherein the integrating means includes anadder, coupled to the HD encoder and the upscaling circuit, that isconfigured to combine the decoded HD enhancement layer and HD formatsignals into the HDTV output.
 12. The terminal of claim 8, furthercomprising means for storing the HD enhancement layer.
 13. The terminalof claim 12, wherein the storing means includes a hard disk.
 14. Amethod for delivering high-definition (HD) TV signals, comprising thesteps of: obtaining an HD enhancement layer containing an HD enhancementdata stream; and delivering the HD enhancement layer to a server toenable a subscriber to access the server, via a set top terminal, toreceive the HD enhancement layer over a network system.
 15. The methodof claim 14, further comprising a step of delivering a base layercontaining a standard definition (SD) data stream to the set topterminal to allow the terminal to integrate the HD enhancement layer andthe base layer into a HDTV output.
 16. The method of claim 15, whereinthe obtaining step includes: generating the base layer; upscaling thebase layer to generate HD format signals; subtracting the HD formatsignals from original HD signals to generate enhanced signals; andencoding the enhanced signals to generate the HD enhancement layer. 17.The method of claim 16, wherein the step of generating the base layerincludes: downscaling HD signals to generate SD format signals; andencoding the SD format signals to generate the base layer.
 18. Themethod of claim 17, wherein the enhanced signals are encoded using ITUH.264 compression technology.
 19. The method of claim 18, wherein the SDformat signals are encoded using MPEG2 compression technology.
 20. Themethod of claim 18, wherein the SD format signals are encoded using ITUH.264 compression technology.
 21. The method of claim 15, wherein thebase layer is delivered via broadcasting.
 22. A method for providing ahigh-definition (HD) TV output, comprising the steps of: decoding ahigh-definition (HD) enhancement layer containing an HD enhanced datastream; decoding a base layer containing a standard-definition (SD) datastream; upscaling the decoded base layer to HD format signals; andintegrating the decoded HD enhancement layer and the HD format signalsinto an HDTV output.
 23. The method of claim 22, wherein the step ofdecoding a base layer includes: tuning the base layer received; anddecoding the base layer.
 24. The method of claim 22, further comprisinga step of storing the HD enhancement layer.
 25. The method of claim 24,further comprising means for erasing the stored HD enhancement layerafter the enhancement layer is accessed by a viewer.